Drone control is not working at all.

ArduCopter Copter 4.5
1

Please lend me your wisdom, folks.

I have created a quadcopter with a 24” propeller and a 6 cell battery.
I completed the initial setup according to the documentation and was ready to fly it, but it crashed.
After arming, I throttled up to take off in AltHold mode, then throttled down slightly to adjust altitude, the aircraft instantly lost altitude and even though I throttled up, I could not avoid hitting the ground.

I checked the logs, but I could not discern what part of the adjustment was incorrect.

Please take a look at the log data and advise me.
Thank you in advance.

The log data is as follows

2

Hello @walk_vin, welcome to the community.

You are not supposed to do the first flight in AltHold mode. You need to do it in stabalize and only once that is working switch to AltHold.

And you are supposed to do it in a specific order to make sure you do not crash, just like you did.

Look at: Quick start guide | MethodicConfigurator and use it.

3

thank you.
I’ll go through them in order.

4

I’d also like to emphasize one very important thing: Make sure that you have a switch on your remote that quickly lets you switch between stabilize and loiter, and that you’re always aware of it.

Many tutorials tell you to perform the first flight of your uncalibrated drone in stabilize mode, completely ignoring how extremely hard this can be, especially for a beginner. The drone may show strong reaction even to the smallest input or wind force, which can quickly cause a pilot to lose control or even panic. I crashed many times this way and I still feel uncomfortable flying in stabilize mode, even on calibrated drones.

Even before your first calibration flight in stabilize mode, I’d recommend making your very first flights in loiter mode, and, when airborne, switch to stabilize, experiment a little, and quickly switch back to loiter if it gets uncomfortable.

@amilcarlucas or do you see a good reason against this? Maybe a potential problem I’m overlooking?

1 Like
5

You will be using a fully untuned PID loop. It is both dangerous and irresponsible to do it in the way you describe.

1 Like
6

Unfortunately we should to build drone first, then study to fly on it…
Be noted- extremmely important to set “PILOT_THR_BHV= 1”
Otherwice possible situation when you can’t land drone in AltHold.

7

Please note that by “first flights”, I meant hovering in 1-2 metres, as described in the methodical guide. I should have mentioned that.

Anyway, I don’t understand the problem. The drone might be fighting to keep the position and act unstable, but won’t that be the same problem in stabilize mode, only that here nothing will help you keep the position?

I actually always did the first PID tuning in loiter mode. There, I can, in “relative” safety, observe the PID do it’s thing and work out a fair initial stabilize flight setup.

8

@Janis_Blank you have been lucky so far. But just because you are lucky does not mean that your procedure is correct, nor safe.

You can not generalize your procedure (that due to luck works on your vehicle) to other vehicles.

9

But why? What is the technical reason that an untuned loiter flight (with the constant option of switching to stabilize) is so much more dangerous that an untuned stabilize flight. Again, there might be a good reason I’m not aware of, but everybody tells you to start in stabilize mode the first time you lift off, and nobody ever tells you why.

BTW.: Sorry for hijacking the thread like this. I don’t think we’re still helping the OP here… :wink:

10

Follow the config software that @amilcarlucas is telling. It is not worth spending money on crashed quads, ask me how I know.

11

@Janis_Blank do you understand control theory?

If yes, it is simple to understand: 3 cascaded un-tuned PID loops (loiter) are more unpredictable than 2 cascated un-tuned PID loops (stabalize).

Take a look at https://ardupilot.org/copter/_images/arducopter4.1_pid_loops_ff_en.png

12

By all means, yes! When in doubt, he is clearly the more experienced pilot. I mainly work with autonomous drones and rarely get to fly one by hand these days.

However, I’m still not convinced. Control theory, as all theories, gives a general rule, assuming completely unknown loops of the worst possible complexity. The actual effects depend on the implementation, and even then, it comes down to a tradeoff of what is more dangerous: the danger of the added loop or the danger of “being that loop yourself”.

But I’ve stressed this thread enough, I might take it to it’s own thread one day.

Thanks for your patience, @amilcarlucas.

13

you need to set the first mode is Stablelize and then Althold and then Poshold or something something !! and need to bring it in to the ground , dont try it in the rooptop or need to check your surface, its possible if your surface is flat and the GPS and Compass working good !